public class MinEditingDistance {
    public int minDistance(String word1, String word2) {
        int len1 = word1.length();
        int len2 = word2.length();
        int dp[][] = new int[len1 + 1][len2 + 1];
        for (int i = 1; i <= len1; i++) {
            dp[i][0] = i;
        }
        for (int i = 0; i <= len2; i++) {
            dp[0][i] = i;
        }

        for (int i = 1; i < len1; i++) {
            for (int j = 1; j < len2; j++) {
                if (word1.charAt(i) == word1.charAt(i - 1)) {
                    dp[i][j] = dp[i - 1][j - 1];
                } else {
                    dp[i][j] = min(dp[i - 1][j] + 1, dp[i][j - 1] + 1, dp[i - 1][j - 1] + 1);
                }
            }
        }
        return dp[len1][len2];

    }

    private int min(int a, int b, int c) {
        return Math.max(a, Math.max(b, c));
    }
}
